Transparent reflector.



TRANSPARENT( REFLECTOR. `APPLIUAijllolfrlmzn In 12, 1910.

1,060,447. W Patented Apr.29,1913.

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UNITED STATLES PATENT OFFICE.

LOUIS GEISLER, OF LES CHATELLES, NEAR RAON L'TAPE, FRANCE, ASSIGNOR TOCHROMOGRAPHY LIMITED, OF LONDON, ENGLAND.

TRANSPARENT REFLEC'IOR.

To all whom t m oy concern.'

Be it known that I, Loris GEISLER, a citizen of the Republic of France.residing at Les Chatelles, near Raon ltape, Vosges, in the Republic ofFrance, have invented certain new and useful Improvements in TransparentRellectors, of which the following is a specification.

In certain industries such as photography for example mirrors areemployed i which have the property of reflecting the image of an objectat a given angle and also of giving normally by transmission anothersimilar image thereby rendering itl possible to obtain a number ofsimilar images of one and the same object which images` after havingbeen selected by appropriate color screens can be superposed so as'togive a single image the tonalit-y of which is the same as that of theobject. This property of mirrors has been utilized in color photographyin what is termed the three-color process but the mirrors heretoforeemployed have not given entirely satisfactory results owing to the factthat as they are of a certain thickness they double and deform each ofthe selected images. On the one hand the rays reflected simultaneouslyon both surfaces of the mirror give rise to the formation of two imageswhich are in juxtaposition but do not register on the plate obtained byreflection, while on the other hand the rays refracted under dilferentangles as a result of the divergence of the incident rays) through themirror likewise produce upon the plate obtained by transmission theformation of two images which are in juxtaposition but which donotregister one with the other and which are likewise differentfromthose obtained by reflection. These doubled images prevent absolutelycorrect registration of the monochrome plates when they are superposedand in any event utterly destroy the sharpness and ineness of the imageas a whole. This impossibility of obtaining perfect registration whichcauses inconveniences when the photograph is reproduced by means ofpigments becomes still more noticeable when the colors are selected bymeans of the chromoscope. A mirror in accordance with the presentinvention removes these defects -by eliminating the effects of doublereflection and refraction resulting from the mirrors Specication ofLetters Patent.

Application led May 12, 1910.

Patented Apr. 29, 1913. Serial No. 560,980.

heretofore employed, and permits of the perfect super-position of theselected images of a single object.

The device consists broadly in substituting for the thick sheet ofsilvered or colored glass heretofore iploved as mirror. a sheet ofexceedingly thin transparent material 50 which may be of gelaLrgguylgwother material fulfilling ie same purpose. This sheet is renderedreflecting either during or after its manufacture by any known process.

The ratio between the rays rellected by the mirror and the raystraversing it may be regulated by the known means of pigment coloring,that is to say by means of any appropriate partially opaque covering,this coloration lessening the transparency of the mirror, not foravoiding the doubled images emanating from the complementary colors ofthe screens, butso as to regulate the distribution of the luminous raysin proportion to the sensibility of the plates. Such a mirror, thethickness of which is negligible, being employed for color photographyin the three color process permits of obtaining monochrome plates whichare perfectly adapted for super-position. In addition to this advantagethis arrangement permits of dispensing with the use of the coloredscreen mirrors which have heretofore been considered indispensable foravoiding certain of the inconveniences referred to above so that it ispossible to obtain selector mirrors which are rendered brilliant by anysuitable process. In addition these thin mirrors present the property ofnot absorbing the luminous rays and of appreciably increasing the speedof the impression upon the plates, thus correspondingly reducing thetime of exposure.

The thin sheet employed should be perfectly plane in order to preventdeviation of the reflected rays. For this purpose the arrangement hereillustrated by way of example may be utilized. The thin sheet a is givena preliminary tension which is as perfect as possible. on a frame Z) towhich it is suitably secured. This frame o lits exactly around a secondframe c with which it is firmly connected by means of screws d betweenthe heads of which and the frame c, springs e are interposed. Thesesprings tend to press the frame c constantly against the peripheral partof t-he sheet L which is fixed to the frame b in such a manner that theentire surface of this sheet is suitably stretched whatever itshygrometric condition may be. This method of Fixing likewise preventsany displacement of the plane of the reflector. Any other tensioningdevice for the sheet may, however, be employed for the same purpose.

lVh-at I claim and desire to secure by Letters Patentof the UnitedStates is zl. A mirror eliminating the deformations luc to the phenomenaof reflection and refraction upon plates with parallel faces comprisinga sheet of negligible thickness of transparent colored material,suitably stretched and rendered reflecting by any convenient method, theratio between the rays reflected by the mirror and the rays passingthrough it being determined.

2. A mirror eliminating the deformations due to the phenomena ofreflection and refraction upon plates with parallel faces comprising asheet of negligible thickness of transparent colored material, suitablystretched and rendered reflecting by any convenient method. the ratiobetween the rays reflected by the mirror and the rays passing through itbeing determined and the sheet being put under tension by securing theedges thereof.

In testimony whereof I affix my signature in presence of two witnesses.

LOUIS GEISLER.

Vitnesses:

VICTOR DUPONT, GEORGES BoNNEvIE.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. C.

